Stationary storage and mooring plant resting on the bottom of the sea

ABSTRACT

A stationary plant for servicing ships comprises a mooring structure resting on the bottom of the sea and projecting upwardly above the surface of the sea. The mooring structure extends around a central area to generally enclose that area to form a generally enclosed sheltered harbour having at least one entrance for vessels, and the mooring structure comprises at least one hollow water-tight caisson capable of storing a liquid such as oil, gas or the like.

United States Patent 3,779,024 Greve Dec. 18, 1973 STATIONARY STORAGEAND MOORING 1,423,884 7/1922 Rush 61/49 PLANT T G ON T BOTTOM O3,492,826 2/1970 Horstketter. 61/49 THE SEA 2,071,520 2/1937 Harrison61/4 2,939,290 6/1960 Crake 61/46.5 [75] Inventor: Gottfred Greve, Oslo,Norway 3,572,278 3/1971 Knapp et a1. 61 /46.5 X 3,488,967 1/1970 Toossi61/46.5 [73] Assignee: A/S Hoyer-Ellefsen, Oslo, Norway Filed J 21 1971FOREIGN PATENTS OR APPLICATIONS 1 1,413,074 8/1965 France 61/1 R [21]Appl. No.: 155,136

Primary Examiner-Jacob Shapiro [30] Foreign Application Priority Data Aym y et June 23, 1970 Norway 2442/70 [57] ABSTRACT [52] US. Cl. .l 61/46[5 I] In CI E02, 17/00 Eozd 5/00 B63) 35/02 A stationary plant forservicing ships comprises a l 58] Fi d a h 61 M 50 52 mooring structureresting on the bottom of the sea and e e W projecting upwardly above thesurface of the sea. The mooring structure extends around a central areato generally enclose that area to form a generally en- [56] Referencescued closed sheltered harbour having at least one entrance UNITED STATESPATENTS for vessels, and the mooring structure comprises at 3,630,16112/1971 Georgii 6 l/46.5 least one hollow water-tight caisson capable ofstoring 3,618,327 11/1971 Frein et al. 61/34 a liquid such as oil gas orthe 3,660,954 5/1972 Logan 52/309 3,563,041 2/197! Michel 61/46 11Claims, 2 Drawing Figures o at o l 0 /3 f o 0 o I o I ,4 4 O 12 m o 0 lO a PATENTED DEC] 8 I975 M o@ooooo ooo ooo %Mvooo STATIONARY STORAGE ANDMOORING PLANT RESTING ON THE BOTTOM OF THE SEA The present inventionrelates to a stationary plant resting on the bottom of the sea andprojecting above the sea level as well as constructed for anchoringvessels.

The new and characterizing idea forming the basis of the presentinvention is the idea that such a stationary mooring plant can beconstructed so as to comprise storage tanks in the form of caissons orthe like which are suited to receive natural raw materials as forinstance oil or gas.

The invention is especially intended for use in connection with oil orgas sources in the heavy seas where the materials won can be feddirectly into the storage tanks which constitute the main part of theplant structure. Tankers can then anchor alongside said storage tanks toload the oil or the gas.

In this connection it should be mentioned that harbors consisting ofcaissons are previously known. Said caissons, however, are filled withsand, stones or the like and form a purely structural element of aconventional wharf. The previously known structures of similar kind haveonly been located on moderate depths in close connection with a shore.

It should also be mentioned that storage tanks placed on the bottom ofthe sea are known. Said storage tanks, however, have been solely used asstorage tanks having no structural features whatever to permit mooringof vessels. They have provided no protection against heavy sea, no quay,no fenders and no area for storage of goods or mounting of cranes,harbor warehouses, industrial offices, crews quarters or the like. Itis, in fact, typical that storage tanks of the mentioned kind are onlyknown from areas in smooth sea not far from the shore, where vessels cananchor without need of any harbor.

As mentioned, the present invention, on the other hand, is based on theidea that the mooring plant consists of specially shaped storage tanks.It is adaptable to any desired and conventional use of a harbor and maybe positioned and served satisfactorily in any sea area withoutlimitations. The plant according to the present invention will only beunsuitable economically at great sea depths.

The plant is especially useful in shallow sea areas far from the shoreand in areas with much heavy weather, eg in the North Sea. In such acase the previously known storage tanks on the sea ground would beunsuitable because vessels would arrive irregularly, which again causesneed for enormous storage capacity and expensive transport. A plantaccording to the present invention is also advantageous because of itsspace for crews quarters, industry etc.

If the water depth is so large that the caissons would have to bedisproportionately big, the sea ground may be elevated. Thus a fill maybe provided on which the caissons is placed. The fill will normally bemade of stone or sand. I

To achieve the necessary stability the caissons may partly be filledwith sand, stone or similar material. Out of stability considerations itwould also be suitable if the caissons are made reinforced concretestructures.

A caisson could advantageously be divided into several smaller cells orin other words: several caissons can be assembled to a large caisson.The sides exposed to waves are formed in such a manner that the wavesare 2 broken down or subdued. This is especially the case on the waterlevel. For instance a corrugation, a grill or a series of piles could beprovided.

The invention will now be described with reference to an illustratingembodiment shown in the drawing, where FIG. 1 shows a perspective planview of a plant according to the invention, arranged as a partly closedharbor, and

FIG. 2 shows a section along the line A--A in FIG. I.

1 is the mooring structure built of caissons 2. The latter are partlyconstructed as storage tanks for oil 3 and partly as chambers for sand4. Interior walls 5 divide the caissons into cells and 6 is a coverdividing the spaces for oil and sand. 7 is a stone fill arranged toelevate the bottom of the sea below the caissons. The partly closedharbor basin provided by the embodiment according to FIG. 1 is marked 8.Here vessels 9 can find lee shelter. The deck 10 can be used formanufacturing premises, crews quarters, helicopter deck or the like. Theportion of the mooring structure exposed to waves is preferably made insuch a manner as to subdue or break the waves. Such means may includecorrugations 11. In addition, piles, grills or the like indicated as 12in FIG. 1 may be provided at a distance from the mooring structure forbreaking down the energy of the waves before they reach the mooringstructure. The top of the mooring structure 1 would preferably includeat least one flat portion adapted to-serve as a helicopter deck, ahelicopter being indicated schematically at 13 in FIG. 1. The concretewalls of the storage tanks are preferably finished with a plasticcoating.

It will be understood that the embodiment of the plant according to theinvention shown in the drawing and described above is only intended asan illustration of the inventive idea, and can be varied in many wayswithin the scope of the invention. It is essential that storage tanksare arranged in such a manner that a suitable mooring possibility isprovided, which is adapted in each case to the desired storage capacity,protection against heavy weather, quay area etc.

I claim:

1. A stationary plant for servicing ships comprising:

a mooring structure resting on the bottom of the sea and projectingupwardly above the surface of the sea, said mooring structure extendingaround a central area to generally enclose that area to form a generallyenclosed sheltered harbor having at least one entrance for vessels, saidmooring structure comprising at least one hollow water-tight caissoncapable of storing a liquid such as oil, gas or the like.

2. A plant according to claim 1, said mooring structure beingconstructed from its bottom to its top of a plurality of individualcaissons forming a plurality of cells watertightly separated from eachother.

3. A plant according to claim 1, in which the outer periphery of themooring structure exposed to waves said mooring structure resting onsaid till.

10. A plant according to claim 1, wherein the storage capacity of thecaissons is more than 100,000 tons of oil.

11. A plant according to claim 1, wherein said at least one caisson hasconcrete walls finished with a plastic coating.

1. A stationary plant for servicing ships comprising: a mooring structure resting on the bottom of the sea and projecting upwardly above the surface of the sea, said mooring structure extending around a central area to generally enclose that area to form a generally enclosed sheltered harbor having at least one entrance for vessels, said mooring structure comprising at least one hollow water-tight caisson capable of storing a liquid such as oil, gas or the like.
 2. A plant according to claim 1, said mooring structure being constructed from its bottom to its top of a plurality of individual caissons forming a plurality of cells watertightly separated from each other.
 3. A plant according to claim 1, in which the outer periphery of the mooring structure exposed to waves includes means for breaking down the waves.
 4. A plant according to claim 3, wherein the means for breaking down the waves include a corrugated surface on the outer periphery of the mooring structure.
 5. A plant according to claim 1, including a means provided at a distance spaced outwardly from the mooring structure for breaking the energy of the waves before they reach the mooring structure.
 6. A plant according to claim 1, in which the caisson is at least partially filled with sand, stone Or the like.
 7. A plant according to claim 1, wherein the plant is arranged as an island in open sea.
 8. A plant according to claim 1, wherein at least a portion of the top of the structure is generally flat, and is constructed as a helicopter deck.
 9. A plant according to claim 1, including a fill of stone, sand or the like on the bottom of the sea, and said mooring structure resting on said fill.
 10. A plant according to claim 1, wherein the storage capacity of the caissons is more than 100,000 tons of oil.
 11. A plant according to claim 1, wherein said at least one caisson has concrete walls finished with a plastic coating. 